Today the malfunction light, the one that looks like an amber motor came on. I looked a the owners manual and checked the fuel cap. Guess what? It had not been tightened by the full service station that I went to for my last fill up. Well the cap was reset correctly but the light hasn't gone off after a day of on and off driving. Does anyone have an idea of how long this might take? Or will I need to visit the dealer? Seems kind of silly for an un tightened gas cap.

Follow Up. I filled the tank with gas from a station that I don't normally use. Then I drove the car for two days about 200 km or about 120 Miles. Finally the indicator went off. I takes a long time to clear. Nothing should take this long to reset after a gas cap was loose or not on.

I recommend to anyone that owns a modern vehicle to invest in a code reader. They are not expensive (under $50 at Walmart), and will let you read the code that generated the Malfunction Indicator Light (MIL), take remediation action, and clear the code yourself. While the terminology used for each of the codes can be very confusing when trying to figure out what it is trying to tell you, a brief search on the Internet using the code and/or description will usually give you several things that might be causing the problem. Even if you don't want to try to fix it yourself, at least you have some idea of what the truck thought was wrong before you take it in to the dealer.

... and if you decide you don't want to fix it yourself, then don't clear the code -- the mechanic needs it.

My $80 code reader (bought several years ago when they were pricier) has saved me well over $2000 so far in simple stuff I could fix myself.